1. Rich Marini Department of Horticulture Penn State University
Vegetable Garden
Rich Marini
Department of Horticulture
Penn State University

2. Unit 1: Garden Planning (Let’s Plan)
Preparing for a Vegetable Garden
Making the most of the Garden Space

3. Preparing for a Garden Develop plans in February
Select a site – avoid shade, poor soil, wet and low areas, and walnut trees
List the vegetable species & varieties – consider season
Decide how much to grow – how will produce be used
Make a planting map

4. Planting Map (24’ x 50’) gr. beans (4/15) gr. beans (5/8) North
pumpkins
melons 6’
spinach (3/20) lettuce(3/20) radishes (3/20)
Onions (4/1)
gr. beans (4/15) gr. beans (5/8)
carrots (4/15) peppers (5/15) 2’ 2’ 3’ 4’
corn (4/15) corn (5/1) corn (5/15) 3’
corn (4/15) corn (5/1) corn (5/15) 3’
North

5. Planning suggestions Put vine crops on the edge
Plant 3 rows of corn for pollination
Put tall plants on north side
Plant small amounts several times to extent the harvest season
1,000 sq. ft. takes about 1 hr per week of care

6. Other considerations
Rather than rows, can plant broadcast (no rows), but rows are easier to care for
Consider equipment size for row spacing
Double crop to use space efficiently – Harvest radishes, peas, lettuce early then plant late-season crops in same space (peppers, beans, summer squash)

7. Develop a Garden Calendar
January – look at seed catalogues
February – Order seeds
March – Plant peppers indoors, test soil
April – plant early season crops
May – Sept. – grow garden
Oct. – clean up garden

8. Unit 2. Planting a Garden
Understanding soils – soils provide support, water, and mineral nutrients
Soil is composed of sand, silt, clay and organic matter
Soil has living organisms – worms, insects, fungi, bacteria: some are pests, some are beneficial
If too much clay, add organic matter

9. Soil Chemistry Soil pH should be slightly acid (6.0 – 6.8)
Too low: macronutrients are deficient
Too high: micronutrients become toxic
Macros: N, P, K, Ca, Mg
Micros: Fe, Cu, Mn, B, S, Zn
Most soils have enough of everything except N,P,K – complete fertilizer

10. Soil Physical Characteristics
Sand – large particles, good for water drainage
Clay – very small particles, holds lots of nutrients, hard to dig, poor water movement
Silt – intermediate size, water moves slowly
Organic matter – holds water and provides nutrients and supports micro-organisms

11. Buying plants & seeds Buy current season’s seeds
May have to order unusual varieties
Look for disease resistant varieties
Buy good-quality plants – look for new shipments – avoid yellow or wilted plants

12. Artificial Soil Mixes Fewer disease problems than real soil
Usually contain fertilizer
Some brands better than others
I like “Mirical-Gro”, but others may be good
Usually contain peat, vermiculite & perlite and fertilizer

13. Starting Plants Indoors
Need warm sunny place
Don’t start too early, plants will be pot-bound and “leggy”
Transplant to pots when about 1.5” tall
Put outdoors as soon as possible

14. Planting in the garden
Cultivate the soil and incorporate fertilizer and lime
Use string to make straight rows
Small seeds are barely covered, plant large seeds 2 times their diameter in depth
Thin plants to appropriate distance – follow directions on the packet

15. Transplanting “Harden” plants by growing outdoors for about a week
Plant at about the same depth as in pot
Remove peat-pot bottom and side
Water
Avoid hot sunny, windy days

16. 3. While You wait – Plant Science
Seeds – a seed is an embryo, a tiny plant with root parts, a stem, and about 6 leaves. A seed coat protects the embryo
Have a food supply until there is adequate foliage to produce enough carbohydrate
Endosperm and cotyledons (specialized leaves) – starch (corn & wheat) or oil (beans). Coconut “milk” is liquid endosperm.

17. Two kinds of plants Monocots: one cotyledons – grasses
Dicots: two cotyledons – beans, apple, maple, tomato

18. Seeds and Seedling

19. Dicot and Monocot Seedling

20. Dicot Seedling
True leaf
Cotyledons

21. Conditions for seed germination
Seeds are living organs
Need Oxygen for respiration to generate energy from food supplies
Need Water (imbibition) for cell expansion and for photosynthesis and biochemical reactions
Proper temperature – 45 degrees for lettuce, 70 degrees for pepper

22. Water and air enter through the seed coat and carbon dioxide exit through the coat.
Some seeds (lettuce) require light (red light) to stimulation of hormones
If planted too deep, leaves don’t reach light before food reserves are used up.
Some seeds have hard thick seed coats and must be scarified (stratch the seed coat) to allow water in.

23. Germination requirements
Seed coats also contain “inhibitors” and some need to soak to leach out inhibitors.
Some seeds require a chilling period (vernalization) to break dormancy (apple seeds need 1,000 hrs below 45 degrees F)
Hormones (gibberellins) may overcome dormancy

24. Common reasons for lack of germination
Improper soil temperature
Soil too dry
Seeds planted too deep
Seeds washed away
Damping-off disease (fungus)

25. Basic Plant Needs Light Water Mineral nutrients
Air (oxygen & carbon dioxide)
Proper temperature

26. Photosynthesis A biochemical reaction in the cells of green tissues.
Chlorophyll is the green pigment in organelles called chloroplasts

27. Photosynthesis
Requires the green pigment (chlorophyll) in the chloroplast within the cell.
The light cycle requires light for energy . Water is split into hydrogen and oxygen.
The dark cycle occurs in the dark or light where hydrogen combines with carbon dioxide to form glucose. Oxygen is passed through the stomates.
Glucose or sucrose transported through the phloem throughout the plant.

28. Light for photosynthesis
Chlorophyll absorbs light energy to convert carbon dioxide and water into sugars. Oxygen is also produced. Gases (oxygen, carbon dioxide & water) pass in and out of leaves through small holes called stomates.

29. Respiration
Within specialized organelles (mitochondria) in the cells, sugars are converted to energy which is used for plant growth. Oxygen is used and carbon dioxide is produced.

30. Plant parts - Roots
May store sugars (sugar beet, carrot) or starch (woody roots, sweet potato)
2 types of roots
Primary tap root: long strong roots (some trees, carrots, dandelion)
Fibrous roots: short thin roots arising from larger roots (beans & tomato)
Root hairs are extensions of cells on the root surface (epidermal cells). These very small structures absorb most of the water and nutrients.

31. Root Motion
Roots normally grow down. They are sensitive to gravity (geotropism).

32. Stems
Connect leaves and roots, and supports leaves for light exposure. Similar to a pipe. Water and mineral nutrients move up in the xylem. Sugar solution moves down in the phloem.
Some stems store food – starch in potato, starch in tree trunks in winter, sugar in sugar cane.

33. Simplified stem cross-section
Epidermis -
Xylem
Phloem

34. Longitudinal section of a woody stem

35. Stem function Epidermis – one layer of waxy cells Phloem – live cells
Xylem – long dead cells lined up end-to-end to produce a “pipe”
Vascular Cambium – a cylinder several cells thick between the phloem and xylem. Responsible for diameter increase: produces xylem cells to the inside and phloem cells to the outside

36. Geotropism A plants grow in response to gravity
Positive geotropism – roots bend toward gravity
Negative geotropism – stems bend away from gravity
Curvature is caused by unequal growth on the 2 sides of the axis

37. Auxin – a plant hormone
Produced in young leaves, shoot tips (meristems) and seeds.
Auxin moves with gravity, causes bud dormancy and causes cell elongation

38. Growing tip

39. Tomato Gravitropism

40. Phototropism
Auxin
Auxin

41. Motion of stems
Phototropism - Stems bend toward light. Auxin is destroyed by light, so cells on the dark side elongate and cause bending toward light.
Auxin produced in the shoot tip moves down the stem and accumulates on the lower side of the stem, so stems bend up.
Root growth in inhibited by auxin. Auxin accumulates on lower side, so roots grow down

42. Apical dominance Buds actually are short stems with about 6 leaves.
Auxin moves from the apex down and inhibits buds. Removing the apex (pinching) allows the buds below the apex to grow. This causes branching.

43. Carbohydrate transport
Sugars can be used for energy or converted to structural molecules such as cellulose (cell walls), fats and proteins.
Sugars move from areas of high concentration (leaves) to areas of low concentration in the phloem.

44. Flowers – modified stems
At some point buds switch from vegetative to reproductive – environmental cues.
Flowers are reproductive structures and attractive insects.
Pollen produced on anthers is transferred to the stigma, then germinates and grows down the style to the ovary where the sperm fertilizes egg to produce a seed.

45. Types of flowers
Perfect flowers have both pistils and stamens (peas, bean, tomato, apple)
Imperfect flowers are either male or female (cucumbers, melons, squash).
Some species have male and female plants (ginko trees).

46. Flower Parts

47. Fruits
As ovules develop into seeds within the ovary, the ovary swells and becomes fleshy or hardens to protect the seeds. Fruit helps seeds disseminate.
Fleshy fruit (squash, tomato, grape) have fleshy ovaries surrounding the seeds.
Dry fruits have ovaries with thin, dry walls. Corn, wheat, oats and each fruit is a single seed. Beans are dry fruits with a nonfleshy pod containing several seeds.

48. Seeds

49. Varieties of bean seeds

50. Tomato Fruit with Seeds

51. Bean fruit and seed

52. How do we make new plants? Plant Propagation
Sexual – from seeds: Allows a species to survive by perpetuating genetic variation
Asexual or vegetative – produce new plants from parts of a plant to maintain genetic identify. Produces clones.

53. Vegetative propagation
Stems – potato, bulbs
Cuttings – roots can be produced by leaves or stems
Grafting – join a scion variety onto a rootstock
scion
Match up
cambiums
rootstock

54. Plant Life Cycle Seeds geminate Plant grows, matures, and flowers
Produces fruit and seeds
Plant dies
Annuals live 1 year (lettuce, beans)
Biennials flower second year, then die (carrot, onion)
Perennials live many years (asparagus)

55. Plant improvement
Natural selection: In the wild, individuals within a species differ. Those with characteristics enabling them to survive to reproductive age pass on their genes to the next generation.
Man has domesticated plants and animals by selecting individuals with the characteristics we want.

56. Plant breeding
Plant breeding: During the last century we have controlled pollination to develop hybrids or new varieties with outstanding characteristics
Examples include high yield, large fruit, different flower colors, disease resistance.
There is some concern that we have reduced genetic variation too much, new strains of disease may devastate a crop

57. Biotechnology A set of techniques used to study and modify genes.
Examples
FLAVR SAVR tomato – doesn’t produce the ripening hormone ethylene, so it can be stored a long time before exposing it to ethylene to cause ripening
Some corn varieties contain the BT gene for resistance to worms

58. Genetic Engineering
Transferring specific genetic material from one organism to another.
Examples: Put the gene from a firefly into a tobacco plant and the plant glows in the dark.
Put an antibacterial gene from a moth into an apple tree to make it resistant to bacteria.

59. Preserving genetic diversity
We want to save genetic variation to use in breeding programs. USDA maintains repositories for major crops; both seeds and plants.
USDA funds plant collecting expeditions to “centers of origin” for major crop species

60. Interdependence (Ecology)
All organisms are connected. Some plants rely on animals to transfer pollen and disseminate seed. Some plants rely on fungi to improve root function.
Animals rely on plants to convert solar energy (sun light) to chemical energy (sugars)

61. Human impact on ecology
Acid rain is killing the eastern forest
Ozone, from car emissions, injures some plant species
Pesticides and other chemicals may injure non-target organisms
Global warming may alter the distribution of organisms and agricultural productivity

62. Hydroponics
We can provide support and nutrients for plants without soil
Commercial greenhouse tomatoes are often grown hydroponically in shallow trays of flowing water containing fertilizer.
Most greenhouse crops are grown in soiless mixes of sand, perlite, vermiculite, and peat

63. Unit 4. Garden Care
Soil fertility – At least 2 months before planting contact local Extension office for soil testing kit. Fertilize & lime according to recommendations.
Apply lime to raise soil pH and reduce acidity (about 6.2 to 6.8)
Apply complete fertilizer to provide nitrogen, phosphorous, potassium

64. Organic Matter
Organic matter provides nutrients and improves soil structure and water holding capacity. Also encourages many soil organisms – worms, insects, fungi, bacteria
Sources – compost, manure, bone meal

65. Garden Equipment
Hoe, rake, trowel, watering can, hose, short stakes and string to mark rows, long stakes for supporting plants, hot caps, sprayer, tiller
Pesticides – read the label
Store locked up
Leave in original container
Avoid freezing or hot environments

66. Frost
Site selection – avoid low areas because cold air is heavier than warm air and flows down hill just like water.
Tender plants, such as tomato, peppers, squash are killed at about 30° F
Cool season crops, such as cabbage, broccoli tolerate a light frost (27° F), and carrots, beets, lettuce tolerate 22° F

67. Frost protection
Cover plants with hot caps, newspaper tents, or mulch with straw
Overhead irrigation
Late season frost – harvest as much as possible before the frost

68. How does irrigation work?
As water freezes it releases heat. Ice provides little insulation, so irrigation must continue to freeze until the temperature increases above 32° F and all ice has melted
Don’t irrigate when due point is low and there is wind because evaporation requires heat and heat will be removed from plants

69. How do hot caps work? Greenhouse effect
During the day short-wave solar radiation is absorbed by soil and exits the soil at night as long-wave radiation. Hot caps provide a barrier to long-wave lengths which are redirected toward the soil. Frosts are rare on cloudy nights because clouds allow short waves, but not long waves, to pass through.

70. Managing weeds Weeds are plants growing where they are not wanted
Weeds compete for light, water & nutrients
Best to eliminate weeds when small
Mechanical control – pull by hand, hoe, cultivation. This must be done every 10 to 14 days depending on rain. Weed seeds can remain dormant in soil for many years.

71. Mulch to control weeds
Can use straw, shredded paper, thin layer of grass clippings or plastic
Also helps conserve water, reduces soil erosion and keeps plants clean
Apply mulch early, before weeds come up

72. Herbicides Chemicals that control weeds
May control grasses, broadleafs or both
Pre-emergent herbicides prevent seeds germination
Post-emergent herbicides kill plants on contact
Not recommended for home garden

73. Plant diseases Infection requires
Susceptible host plant
Presence of the pathogen
Proper environment for disease development
Powdery mildew requires hot dry conditions, and early blight on tomato requires wet conditions
Viruses spread by insect vectors

74. Managing plant diseases
Caused by fungi, bacteria, nematodes or virus
Select resistant varieties when possible
Encourage quick drying – avoid shade, control weeds, leave space between plants

75. Controlling diseases
Cultural control – good drying conditions, resistant varieties, remove diseased plants
Fungicides and antibiotics – these are preventative and must be applied before infection occurs. Apply every 10 to 14 days to protect new growth and replace residue washed off by rain.

76. Diseases of squash
Powdery mildew
Septoria leaf spot
Virus

77. Non-pathogenic problems
Sunscald heat injury to fruit
Cold growing conditions can cause plants to turn purple due to poor phosphorous uptake
Too much fertilizer can burn roots and cause wilting
Too much pesticide can damage leaves

78. Insect pests Many types of insects can feed on plants.
Grubs (immature beetles) feed on roots
Worms (immature moths) feed on leaves, fruit, or tunnel into stems (borers)
Maggots (immature flies) feed on fruit & roots
Beetles, aphids, and true bugs feed on leaves

79. Japanese beetle life cycle

80. Controlling insects
No resistant varieties, except for genetically modified varieties of corn and soybeans (BT genes)
Use insecticides to kill insects
Monitor plants every week
Don’t apply until you see pests
Use “soft’ materials that protect nontarget organisms

81. Aphids

82. Corn Ear Worm Life Cycle
Adult
Larvae
Pupae

83. Natural vs. man-made pesticides
All are poisonous and should be treated with care
Natural materials usually are broad-spectrum and kill nontarget species, and they must be applied more frequently because they are less residual
Insecticidal soaps are effective
Many insects are beneficial and we want to protect them

84. 5. Harvest & storage
Important to harvest vegetables at proper stage. If many leafy vegetables are left too long, they will produce flowers
Peppers are ready when they are full size, can wait and harvest them red
Tomato can be harvested when just beginning to turn red
Cantaloupes are harvested when stem slips off the melon

85. Other vegetables
Zucchini, summer squash, and cucumbers are harvested when fairly small (before seeds enlarge) and need to be harvested every day or two.
Potatoes are harvested when leaves start to die in late summer
Onions are mature when leaves fall over

86. Storage
Harvested plant parts are living tissues and continue to respire. We want to slow down respiration so the cells remain alive
High humidity for leafy vegetables – put in perforated poly bags
Temperature is most important
Most vegetables store well in the refrigerator (about 40ºF)
Peppers store at about 50ºF

87. Unit 6: Careers Without a college degree
Farm, greenhouse, florist worker
Assistant manager, retail market
Landscape worker
2-yr Associate degree in plant science
Assistant superintendent for golf course
Farm & retail store manger
Arborist, flower shop manager

88. 4-yr degree programs
Crop protection – entomology, plant pathology, weed science
Environmental sciences
Ag economics - farm management, rural development
Horticulture, landscape architecture & landscape contracting
Plant genetics & plant breeding

89. Careers with B.S. degree Teach agriculture and science
Ag. Chemical sales, exterminator
Government agencies (USDA, DEP, EPA)
Manager of farms, retail centers, nurseries, flower shop
Landscape architect, Landscape contractor, golf course superintendent
Plant breeder

90. Careers with M.S. degree
Research technician with chemical company, university, USDA, private lab
Plant breeder
Produce wholesale & marketing
International agriculture
Government agencies
Ag sales and marketing
Extension agent
Teach at community college
Public gardens & arboreta

91. Careers with Ph.D. Academia (teach, research, extension)
Ag. Chemical company R&D
International agriculture
Plant breeder
Industrial research – Ag. Chemicals, plastics, greenhouses
Marketing
Government agencies (USDA, EPA, DOE, DEP, PDA)

92. Other considerations
Rather than rows, can plant broadcast (no rows), but rows are easier to care for
Consider equipment size for row spacing
Double crop to use space efficiently – Harvest radishes, peas, lettuce early then plant late-season crops in same space (peppers, beans, summer squash)